It might be hard to recall a time when we didn’t know that exercise is good for your heart, and smoking is bad for it – but, back in 1948, researchers and clinicians knew little about the causes of cardiovascular disease. That year, the National Heart Institute (now the National Heart, Lung, and Blood Institute, part of the National Institutes of Health) launched the ambitious Framingham Heart Study to “identify the common factors or characteristics that contribute to CVD by following its development over a long period of time in a large group of participants who had not yet developed overt symptoms of CVD or suffered a heart attack or stroke.”

Researchers recruited 5,209 study participants from the town of Framingham, Massachusetts; these volunteers show up for an extensive checkup once every two years, submitting to multiple lab tests and completing lifestyle questionnaires. In 1971, the study enrolled 5,124 of the original participants’ adult children and their spouses – and it’s now recruiting the Third Generation cohort. From all the Framingham data, researchers have learned a great deal about how lifestyle factors can affect CVD risk. Here are some of the Most Significant Research Milestones from the NHLBI’s Framingham Heart Study website:

1960: Cigarette smoking found to increase the risk of heart disease
1961: Cholesterol level, blood pressure, and electrocardiogram abnormalities found to increase the risk of heart disease
1967: Physical activity found to reduce the risk of heart disease and obesity to increase the risk of heart disease
1970: High blood pressure found to increase the risk of stroke
1976: Menopause found to increase the risk of heart disease
1978: Psychosocial factors found to affect heart disease
1988: High levels of HDL cholesterol found to reduce risk of death
1994: Enlarged left ventricle (one of two lower chambers of the heart) shown to increase the risk of stroke
1996: Progression from hypertension to heart failure described

A tribute to participants on the study’s 50th anniversary thanks the Framingham volunteers for contributing so much to the world’s health:

Thanks to You:

High cholesterol, high blood pressure, smoking, obesity and diabetes were identified as “risk factors”– a term coined by the Study – for cardiovascular disease.

We heard the groundbreaking news that we could modify these risk factors.

Physicians began to practice preventive medicine, checking for risk factors, questioning their patients about lifestyle and encouraging positive changes.

We learned that sickness and health result from a complex mix of nature and nurture.

Genetic causes for risk factors are being discovered.

We gained new perspectives on many other diseases, including cancer, arthritis, osteoporosis, eye disease, hearing problems and dementia.

We learned that we can do our part, as a society, to promote healthier lifestyles for longer lives.

In a segment on the latest Living on Earth show, Bruce Gellerman interviews some of the participants who’ve contributed so much to our knowledge about CVD and other diseases. Here he is speaking with 94-year-old Walter Sullivan, one of the original participants, and study director Dr. Daniel Levy:

SULLIVAN: This will be my 30th next year, every two years for 60 years. I look forward to it.

GELLERMAN: Your participation in this study, it seems to me may have contributed to extending the lives of countless numbers of people.

SULLIVAN: Well I’m so happy with the reaction of the people of Framingham. They were doing something with their fellow citizens that was helpful to society. So, it’s a good feeling, especially for a kid who grew up in Framingham.

GELLERMAN: Walter Sullivan’s three children and now seven of his grandchildren also participate in the heart study. Again, director Daniel Levy:

LEVY: When we recruited our third generation of participants, literally there was hardly a day that went by when one of these 3rd generation individuals did not come in and say, ‘I have waited all my life for this day to come.’ And every time I heard someone say that, it gave me goose bumps.